Printing phosphor on led wafer using dry film lithography

ABSTRACT

A method for depositing a layer of phosphor-containing material on a plurality of LED (light-emitting diode) dies on a wafer includes disposing a layer of dry photoresist film over a plurality of LED dies on a wafer, disposing a mask layer over the dry photoresist film, and patterning the dry photoresist film to form a plurality of openings in the dry photoresist film to expose a top surface of each of the LED dies. The method also includes depositing a phosphor-containing material on the exposed top surface of each the LED dies using a screen printing process, and removing the patterned dry photoresist film.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/338,936, Attorney Docket No. 91924-001700US-80856, filedDec. 28, 2011, commonly owned and incorporated herein by reference inits entirety.

This application is also related to U.S. patent application Ser. No.13/338,912, Titled Attorney Docket No. 91924-001600US-808563, filed Dec.28, 2011, and U.S. patent application Ser. No. 13/714,399, AttorneyDocket No. 91924-02500US-808563, filed Dec. 13, 2012, both of which arecommonly owned and incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates in general to light-emitting diodes (LEDs)and in particular to deposition of phosphor-containing material on LEDdies on a wafer.

With the incandescent light bulb producing more heat than light, theworld is eager for more efficient sources of artificial light. LEDs area promising technology and are already widely deployed for specificpurposes, such as traffic signals and flashlights. For colored light, anLED chip is often combined with a wavelength-converting material toobtain desired output light color. For example, yellow phosphors areoften combined with blue LEDs to produce white light. However, thedevelopment of LED-based lamps for general illumination has run intovarious difficulties. Among these is the difficulty of mass-producingLED emitters with phosphors that provide a consistent light color.

Conventional LED emitters often include an LED die in a recess or cupstructure that has phosphor-containing material in the cup. In somecases, the phosphor-containing material is separated from the LED dieby, for example, a silicone material. These conventional methods tendsuffer from many drawbacks. For example, conventional methods often usea large amount of phosphor, and they may cause poor cooling of thephosphor and the silicone material. As a result, the emitter can sufferfrom less reliable packaging and non-uniform angular distribution oflight color. Given existing processes for LED manufacture,mass-producing white LEDs with a consistent color temperature has provento be a challenge.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention relate to methods for placingcontrolled amount of phosphor-containing material on top of LED diesformed on a substrate, such as a semiconductor wafer. A patternedphotoresist can be used to mask out areas of the wafer and the LED dieswhere no phosphor-containing material is desired. In some embodiments,the phosphor-containing material of suitable viscosity is applied, e.g.,by printing, and then excess material is removed using the template as aguide, if needed. The size of the opening limits the phosphor-containingmaterial to only the exposed top surface of the LED dies, and the heightof the template help control the thickness of the phosphor-containingmaterial.

The methods described herein have many advantages that can be achievedover conventional techniques. The methods use conventional equipment andprocesses and are suitable for cost-effective mass production. Thephosphor usage is reduced, since phosphor is placed only on the topsurface of the LED die. Heat generated in the phosphor material can bedissipated through the LED die, and better cooling can reduce thetemperature of the phosphor and the silicone material and lead to morereliable package. In contrast, a conventional method of placing phosphoron die top involves using a syringe to place liquid droplets of phosphormaterial. One drawback of this method is that the liquid mixture tendsto settle and can lead to color shifting. In the methods according tothe present invention, the mixture of phosphor-containing material isformed to desired viscosity before being applied to the plurality of LEDdies on the wafer.

According to some embodiments of the present invention, a method fordepositing a layer of phosphor-containing material on a plurality of LED(light-emitting diode) dies on a wafer includes disposing a layer of dryphotoresist film over a plurality of LED dies on a wafer, disposing amask layer over the dry photoresist film, and patterning the dryphotoresist film to form a plurality of openings in the dry photoresistfilm to expose a top surface of each of the LED dies on the wafer. Themethod also includes depositing a phosphor-containing material on theexposed top surface of each the LED dies using a screen printingprocess, and removing the patterned dry photoresist film.

In an embodiment of the above method, the patterned dry photoresist filmis configured to cover bond pad areas on the LED dies. In anotherembodiment, a depth of the openings in the photoresist layer is equal toa desired thickness of the phosphor-containing material. In anotherembodiment, depositing the phosphor-containing material in each of theopenings in the patterned dry resist film includes depositing thephosphor-containing material on the patterned photoresist layer and theLED dies, and removing the phosphor-containing material from the topsurface of the photoresist layer and on the top surface of the LED diesthat protrudes above the top surface of the patterned resist. In anothermethod, depositing the phosphor-containing material in each of theopenings in the photoresist layer comprises using a screen printingmethod. In some embodiments, the plurality of LEDs is formed on asemiconductor substrate, for example, a silicon wafer , a siliconcarbide (SiC) substrate, or a Sapphire (Al₂O₃) substrate.

According to some embodiments of the invention, a method for depositinga layer of phosphor-containing material on a plurality of LED(light-emitting diode) dies on a substrate includes forming a patternedphotoresist layer over a plurality of LED dies on a substrate, thepatterned photoresist layer having a plurality of openings configured toexpose a top surface of each of the LED dies. The method also includesdepositing a phosphor-containing material on the exposed top surface ofeach the LED dies, and removing the photoresist layer. In a specificembodiment, forming the photoresist layer includes disposing a layer ofdry photoresist film over the template, disposing a mask layer over thedry photoresist film, and forming a plurality of openings in the dryphotoresist film. In an embodiment, depositing the phosphor-containingmaterial in each of the openings in the photoresist layer comprisesusing a screen printing method. In another embodiment, the plurality ofLEDs is formed on a semiconductor substrate. In a specific embodiment,the plurality of LEDs is formed on a silicon wafer.

According to some embodiments of the invention a method for depositing alayer of phosphor-containing material on a plurality of LED(light-emitting diode) dies on a substrate, the method includes forminga template over a plurality of LED dies on the substrate, the templatehaving a plurality of openings configured to expose a top surface ofeach of the LED dies. The method also includes depositing aphosphor-containing material on the exposed top surface of each the LEDdies and removing the template.

In an embodiment of the above method, the template is made of a materialthat can be selectively etched from the phosphor-containing material. Inanother method, the template has a non-sticky surface such that thetemplate can be removed from the deposited phosphor-containing material.In another embodiment, the template is a patterned dry photoresist film.In another embodiment, the plurality of LEDs is formed on asemiconductor substrate for example, a silicon wafer.

A further understanding of the nature and advantages of the presentinvention may be more appreciated by reference to the detaileddescription in the remaining portions of the specification andaccompanying drawings that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-13 are cross-sectional diagrams illustrating a method forcarrying out a method for phosphor deposition according to an embodimentof the present invention.

FIG. 1 shows a substrate for carrying out the method for phosphordeposition according to an embodiment of the present invention;

FIGS. 2 and 3 show a grid template for carrying out the method forphosphor deposition according to an embodiment of the present invention;

FIG. 4 illustrates the process of LED chips being placed into the gridopenings of the template;

FIGS. 5( a)-5(c) illustrate the template openings being filled with LEDchips and bond patterns on the LED chips;

FIG. 6 illustrates a mask layout that can be used in patterning aphotoresist film;

FIG. 7 shows a dry film photoresist disposed over the template and theLED chips;

FIG. 8 illustrates a process of exposing dry film photoresist using aphotomask;

FIG. 9 shows the patterned photoresist after a development process;

FIG. 10 shows phosphor material deposited in openings of the photoresistpatterns;

FIG. 11 shows curing the intermediate structure including a glass plate,a template over the plate, LED chips disposed in openings in thetemplate, a photoresist pattern with a phosphor-containing mixturefilling its openings and over the exposed top surface of the LED chips;

FIG. 12 shows the structure in FIG. 11 with the photoresist removed;

FIG. 13 shows a structure including a plurality of separate LED diesattached to an adhesive tape, each of the LED dies having a layer ofphosphor-containing material on the top surface;

FIG. 14 is a flowchart summarizing the method for depositing a layer ofphosphor-containing material on a plurality of LED dies according to anembodiment of the present invention.

FIG. 15 is a flowchart summarizing a method for depositing a layer ofphosphor-containing material on a plurality of LED (light-emittingdiode) dies on a wafer according to an embodiment of the presentinvention; and

FIGS. 16-21 are simplified cross-sectional views illustrating a methodfor forming a phosphor containing material on LED dies on a wafer.

DETAILED DESCRIPTION OF THE INVENTION

The description below will be made with reference to a series of drawingfigures enumerated above. These diagrams are merely examples, and shouldnot unduly limit the scope of the claims herein. In connection with thevarious aspects illustrated and described, one of ordinary skill in theart would recognize other variations, modifications, and alternatives.

FIG. 1 shows a top view and a cross-sectional view of a substrate forcarrying out the method for phosphor deposition. An adhesive tape 110 isdisposed on a glass plate 120. In an embodiment, the tape is adouble-sided adhesive tape, which can be a thermal release or a UVrelease tape made of, e.g., polyester. For example, a commerciallyavailable tape from Semiconductor Equipment Corp. can be used. Tape 110is attached to plate 120 the glass substrate. In a specific embodiment,plate 120 is about 1 mm thick. But plates having other suitablethicknesses can also be used.

In FIG. 2, a grid template 130 is disposed on the adhesive top side oftape 110. In the example of FIG. 2, the grid template includes openingsarranged in a 6×6 array. However, depending on the application, the gridtemplate can have other grid patterns, e.g. 30×30. In some embodiments,the grid template is a metal plate with square openings. The opening isslightly larger than an LED chip size, and the plate thickness is thesame as the LED chip thickness. A specific example of the template 130is shown in FIG. 3, where the size of the opening 132 is 0.95 mm by 0.95mm for an LED chip of size 0.9 mm by 0.9 mm. In this example, thespacing between openings is 0.5 mm, and the plate thickness is 0.17 mm.Of course, these dimensions can be varied.

In FIG. 4, individual LED chips 140 are placed into the grid openings.For example, a pick-and-place tool can be used to place individual LEDchips into the grid openings, using the grid as fiducia. FIG. 5( a)shows a top view of template 130 with LED chips 140 placed in theopenings. FIG. 5( b) shows a top view of an LED chip which includes bondpad areas 144 that will be shielded from the phosphor layer. Inembodiments of the invention, a dry film photoresist is used to protectbond pad areas, as described below. FIG. 5 (c) shows a desired patternfor exposing the top surface of an LED chip for phosphor materialdeposition while protecting the bond pad areas.

In embodiments of the invention, commercially available dry filmphotoresist is used to mask out areas in the top surface of the LEDdies, such as bond pad areas. For example, the Dupont, Riston series dryfilm resists have a thickness from 20 um to 100 um. The Dupont resisthas negative tone and needs UV light source for lithography. In anotherexample, the 416-DFR dry film resist from MG Chemicals are available inthicknesses from 1.5 to 2 mil. The MG films are also negative tone, butthey can use regular daylight fluorescent light bulb for lithography.The dry film photoresist is often sandwiched between two films, apolyethylene film and a polyester film. In a positive tone resist, thearea to be removed will be exposed and, therefore, appears as open areasin the mask, as illustrated in FIG. 5( c). For a negative tone resist,the areas to be removed in the mask is dark; an example of such a masklayout is shown in FIG. 6. The mask artwork can be made using computergraphics software, and the artwork can be printed on a transparent filmusing, e.g., a laser printer.

In FIG. 7, after the polyethylene layer is peeled off the dry filmresist, the dry film resist 150 is laid over the template 130 with theLED chips 140. The dry film resist is in contact with the LED chips andtemplate. As shown in FIG. 7, the dry resist film can “tent” over thegap between the LED chips and template.

FIG. 8 shows the exposure of the dry resist film. The photo mask 152,with the artwork printed on a transparent film, is disposed over thepolyester cover of the dry film resist 150 that has been adhered to theLED chips/template. The ink side of the photo mask is in contact withthe polyester cover. Next, a UV transparent glass or acrylic plate (notshown) is placed over the top of the photo mark, so that the photo maskcan have a smooth and intimate contact with the polyester cover. Theexposure can be carried out using a UV light source 190, for example,LED lamp LuxSpot Alta from LedEngin can provide 400 um UV light. Theexposure can be carried out for, e.g., 20 minutes. Subsequently, apost-exposure bake is performed to further assist cross links of thephotoresist. The unexposed areas of the photoresist film is removedusing a conventional resist development process. At this point, as shownin FIG. 9, the top surface of the LED dies is exposed, except the bondpad areas. The bond pad areas and the rest of the surface of thetemplate are now protected by the developed photoresist, as shown in thetop view of a die area 154.

In FIG. 10, a phosphor containing mixture 160 is deposited over thepatterned stack. As an example, the mixture can be prepared by mixingsilicone (e.g., Ker2500), phosphors (e.g., yellow and red phosphors),and diluting solution (e.g., KF-994, cyclotetrasiloxane) to achieveproper viscosity and thixotropy. Here, the mixture can have a higherviscosity than the mixture used in conventional liquid dispensingmethods. Therefore, changes in the phosphor mixture caused by settlingcan be reduced. After the phosphor mixture is applied, a degas procedurecan be used to remove bubbles. The mixture is then rolled overphotoresist pattern and print. The printing can be carried out using,e.g., the printing machine from DEK. After printing, excesssilicone/phosphor/dilutent mixture is removed from the stencil. Thethickness of the photoresist allows a controlled thickness of thephosphor mixture on the die top.

FIG. 11 shows the intermediate structure including a glass plate 120, atemplate 130 over the plate, LED chips 140 disposed in openings in thetemplate, a photoresist 150 with a phosphor-containing mixture 160filling the openings in the photoresist and over the exposed top surfaceof the LED chips. This intermediate structure is placed over a hot plate200 to cure the silicone at 120-150° C. for 2 minutes. During curing,the photoresist is maintained at the printing position so silicone doesnot flow and cover the wire bond pads, until thesilicone/phosphor/dilutent mixture is dried.

In FIG. 12, the photoresist is removed. Here, a suitable photoresiststripping solution, such as those from Dupont or MG Chemical, can beused. In FIG. 13, the template is removed, and each individual LED dieis now covered with a layer of phosphor-containing mixture.

A structure shown in FIG. 13 includes a plurality of separate LED dies140 attached to an adhesive tape 110, each of the LED dies having alayer of phosphor-containing material 160 on the die top. At this time,a standard assembly process, e.g., using a pick-and-place tool, can beused to install the phosphor-coated LED dies in an emitter package.

FIG. 14 is a flowchart summarizing a method for depositing a layer ofphosphor-containing material on a plurality of LED (light-emittingdiode) dies according to an embodiment of the present invention. Asshown in FIG. 14, the method includes the following processes:

-   -   disposing a template with a plurality of openings on an adhesive        tape;    -   disposing each of a plurality of LED dies in one of the        plurality of openings of the template;    -   forming a dry film photoresist layer over the template and the        plurality of LED dies, the dry film photoresist layer having a        plurality of openings configured to expose a top surface of each        of the LED dies;    -   depositing a phosphor-containing material on the exposed top        surface of each the LED dies;    -   removing the photoresist film; and    -   removing the template.

An example of the method is described above in connection with FIGS.1-13.

In this method, the process of depositing a phosphor-containing materialon the top surface of each the LED dies includes:

-   -   depositing the phosphor-containing material on the stencil and        the LED dies; and    -   removing phosphor-containing material from the top surface of        the dry film photoresist layer and on the top surface of the LED        dies that protrudes above the top surface of the template.

The methods described above are suitable for phosphor deposition beforethe die attach and wire bonding steps for the single color multi-dieemitters. In addition, in some embodiments, after phosphor printing,each die is tested for light color. Two or more dies of opposite colors(with respect to the average color of all dies) may be selected andattached in a multi-die package.

In some embodiments, the methods described herein can be applied to aplurality of LEDs formed on a conducting carrier substrate. In someembodiments, the methods described herein can be applied to a pluralityof LEDs formed on a semiconductor wafer. For example, GaN (galliumnitride) LEDs can be formed on a SiC (silicon carbide) substrate or asapphire (Al₂O₃) wafers.

In some embodiments, the methods described herein can be applied to aplurality of LEDs grown on a silicon wafer. For example, using siliconwafers as a substrate for GaN epitaxy could reduce the cost, simplifyLED structure, and enable the integration of an optical device with CMOScircuits.

In conventional methods, forming a phosphor layer on LED wafers can bean expensive and non-repeatable process. For example, gold (Au) studbumps are first formed on the LED dies. Then, a phosphor material isdispensed on each LED die, which is often carried out in a slow serialprocess. As a result, the phosphor on the LED dies on the same wafer mayundergo different amount of settling. Next, the wafer goes through agrinding process to remove excess phosphor and expose the gold studbumps. As a result, thickness control of phosphor thickness is difficultto achieve.

Therefore, an improved method for forming a phosphor-containing layer ona plurality of LED dies on a wafer is highly desired.

FIG. 15 is a flowchart summarizing a method for depositing a layer ofphosphor-containing material on a plurality of LED (light-emittingdiode) dies on a wafer according to an embodiment of the presentinvention. As shown in FIG. 15, the method includes the followingprocesses:

-   -   forming a dry film photoresist layer over the template and the        plurality of LED dies, the dry film photoresist layer having a        plurality of openings configured to expose a top surface of each        of the LED dies;    -   depositing a phosphor-containing material on the exposed top        surface of each the LED dies;    -   removing the photoresist film; and    -   further LED wafer processing.

An example of the method is described below in connection with FIGS.16-21.

FIGS. 16-21 are simplified cross-sectional views illustrating a methodfor forming a phosphor containing material on LED dies on a wafer. Theprocesses described here are similar to those illustrated above in FIGS.7-12, in which the LED dies are placed in the openings in a template. Incontrast, in FIGS. 16-21, the LED dies are formed on a substrate, forexample, a semiconductor wafer.

FIG. 16 shows a dry film resist 250 disposed over a wafer 220 thatincludes a plurality of LEDs 240. As described above, wafer 220 can be asemiconductor wafer with LEDs built in it. Alternatively, the LEDs canbe formed on a top surface of the wafer or formed partially in thewafer. Various dry film resists and the processes are described above inconnection with FIGS. 1-7. In FIG. 16, a dry film resist 150 is disposedover wafer 220 with the LEDs 240. In some embodiments, the dry filmresist is in contact with the LEDs and can be in contact with regions ofthe wafer between the LEDs. In some cases, the dry resist film can“tent” over the gaps between the LED chips on the wafer. Such gaps maybe formed during LED wafer processing. For example, wire bond pads maybe disposed below the top surface of the LEDs.

FIG. 17 shows the exposure of the dry resist film in the patterningprocess. A photo mask 152, with the artwork printed on a transparentfilm, is disposed over the dry film resist 150 that has been adhered tothe LED chips on the wafer. The ink side of the photo mask is in contactwith the polyester cover of the dry film resist. Next, a UV transparentglass or acrylic plate (not shown) is disposed over the top of the photomark, so that the photo mask can have a smooth and intimate contact withthe polyester cover. The exposure can be carried out using a UV lightsource 190, for example, LED lamp Luxpot alta from LedEngin can provide400 um UV light. The exposure can be carried out for, e.g., 20 minutes.Subsequently, a post-exposure bake is performed to further assistcross-links of the photoresist. The unexposed regions of the photoresistfilm are removed using a conventional resist development process. Atthis point, as shown in FIG. 18, the top surfaces of the LED dies areexposed by the plurality of openings in the patterned resist, except thebond pad areas. The bond pad areas and the rest of the surface of thewafer are now protected by the developed photoresist, as shown in thetop view of a die area 154.

In FIG. 19, a phosphor containing mixture 160 is deposited over thepatterned photoresist. As an example, the mixture can be prepared bymixing silicone (e.g., Ker2500), phosphors (e.g., yellow and redphosphors), and diluting solution (e.g., KF-994, cyclotetrasiloxane) toachieve proper viscosity and thixotropy. Here, the mixture can have ahigher viscosity that the mixture used in conventional liquid dispensingmethods. Therefore, changes in the phosphor mixture caused by settlingcan be reduced. After the phosphor mixture is applied, a degas procedurecan be used to remove bubbles. The mixture is then deposited over thephotoresist pattern using a screen printing process. The printing can becarried out using, e.g., the printing machine from DEK. After printing,excess silicone/phosphor/dilutent mixture is removed from the wafer. Thethickness of the photoresist allows a controlled thickness of thephosphor mixture on the die top.

In FIG. 19, depositing the phosphor-containing material in each of theopenings in the patterned dry resist film includes depositing thephosphor-containing material on the patterned photoresist layer and theLED dies, and removing the phosphor-containing material from the topsurface of the photoresist layer and on the top surface of the LED diesthat protrudes above the top surface of the patterned resist. In anothermethod, depositing the phosphor-containing material in each of theopenings in the photoresist layer comprises using a screen printingmethod.

FIG. 20 shows an intermediate structure including LED dies 240 in wafer220, patterned photoresist 150 with a phosphor-containing mixture 160filling the openings in the photoresist and over the exposed top surfaceof the LED chips. This intermediate structure is placed over a hot plate200 to cure the silicone, for example, at 120-150° C. for 2 minutes.During curing, the photoresist is maintained at the printing position sosilicone does not flow and cover the wire bond pads, until thesilicone/phosphor/dilutent mixture is dried.

In FIG. 21, the photoresist is removed. Here, a suitable photoresiststripping solution, such as those from Dupont or MG Chemical, can beused. Each individual LED die is now covered with a layer ofphosphor-containing mixture. A structure shown in FIG. 21 includes aplurality of separate LED dies 240 on a wafer 220, each of the LED dieshaving a layer of phosphor-containing material 160 on the die top. Atthis time, a standard manufacturing process can proceed. Themanufacturing process can include wafer probe to determine theelectrical and optical properties of the LED dies, backside wafer polishto reduce thickness, metallization of the backside of the wafer, andwafer dicing to form individual LED chips, etc.

As described above, in some embodiments, the process of depositing aphosphor-containing material on the top surface of each the LED dies ona wafer includes using a screen printing process. In embodiments of thisinvention, the screen printing process provides uniform phosphorthickness and is fast and cost-effective.

In some other embodiments, the process of depositing aphosphor-containing material on the top surface of each the LED diesincludes:

-   -   depositing the phosphor-containing material on the stencil and        the LED dies; and    -   removing phosphor-containing material from the top surface of        the dry film photoresist layer and on the top surface of the LED        dies that protrudes above the top surface of the template.

In the above example, the openings in the patterned photoresist are usedto deposit the phosphor-containing material onto the top surface of LEDdies on a wafer. According to alternative embodiments of the invention,the patterned photoresist film can be replaced by a pre-defined templatehaving a plurality of openings patterned to expose the top surfaces ofthe LED dies. Such a template can be made from a suitable material, suchas metal or plastic. A method for depositing a layer ofphosphor-containing material on a plurality of LED (light-emittingdiode) dies on a substrate, the method includes forming a template overa plurality of LED dies on the substrate, the template having aplurality of openings configured to expose a top surface of each of theLED dies. The method also includes depositing a phosphor-containingmaterial on the exposed top surface of each the LED dies and removingthe template.

In some embodiment of the above method, the template is made of amaterial that can be selectively etched from the phosphor-containingmaterial. In an embodiment, the template is a patterned dry photoresistfilm, which can be etched selectively with respect to thephosphor-containing material. In another method, the template has anon-sticky surface such that the template can be removed from thedeposited phosphor-containing material. For example, the template can bemade of a metal material coated with Teflon. In another embodiment, theplurality of LEDs is formed on a semiconductor substrate for example, asilicon wafer.

Although the invention has been described with respect to specificembodiments, it will be appreciated that the invention is intended tocover all modifications and equivalents within the scope of thefollowing claims.

What is claimed is:
 1. A method for depositing a layer ofphosphor-containing material on a plurality of LED (light-emittingdiode) dies on a wafer, the method comprising: disposing a layer of dryphotoresist film over a plurality of LED dies on a wafer; disposing amask layer over the dry photoresist film; and patterning the dryphotoresist film to form a plurality of openings in the dry photoresistfilm to expose a top surface of each of the LED dies; depositing aphosphor-containing material on the exposed top surface of each the LEDdies using a screen printing process; and removing the patterned dryphotoresist film.
 2. The method of claim 1, wherein the patterned dryphotoresist film is configured to cover bond pad areas on the LED dies.3. The method of claim 1, wherein a depth of the openings in thephotoresist layer is equal to a desired thickness of thephosphor-containing material.
 4. The method of claim 1, whereindepositing the phosphor-containing material in each of the openings inthe patterned dry resist film comprises: depositing thephosphor-containing material on the patterned photoresist layer and theLED dies; and removing the phosphor-containing material from the topsurface of the photoresist layer and on the top surface of the LED diesthat protrudes above the top surface of the stencil.
 5. The method ofclaim 1, wherein depositing the phosphor-containing material in each ofthe openings in the photoresist layer comprises using a screen printingmethod.
 6. The method of claim 1, wherein the plurality of LEDs isformed on a semiconductor substrate.
 7. The method of claim 1, whereinthe plurality of LEDs is formed on a silicon wafer.
 8. The method ofclaim 1, wherein the plurality of LEDs is formed on a silicon carbide(SiC) substrate.
 9. The method of claim 1, wherein the plurality of LEDsis formed on a Sapphire (Al₂O₃) substrate.
 10. A method for depositing alayer of phosphor-containing material on a plurality of LED(light-emitting diode) dies on a substrate, the method comprising:forming a patterned photoresist layer over a plurality of LED dies on asubstrate, the patterned photoresist layer having a plurality ofopenings configured to expose a top surface of each of the LED dies;depositing a phosphor-containing material on the exposed top surface ofeach the LED dies; and removing the photoresist layer.
 11. The method ofclaim 10, wherein forming the photoresist layer comprising: disposing alayer of dry photoresist film over the template; disposing a mask layerover the dry photoresist film; and forming a plurality of openings inthe dry photoresist film.
 12. The method of claim 10, wherein depositingthe phosphor-containing material in each of the openings in thephotoresist layer comprises using a screen printing method.
 13. Themethod of claim 10, wherein the plurality of LEDs is formed on asemiconductor substrate.
 14. The method of claim 10, wherein theplurality of LEDs is formed on a silicon wafer.
 15. A method fordepositing a layer of phosphor-containing material on a plurality of LED(light-emitting diode) dies on a substrate, the method comprising:forming a template over a plurality of LED dies on a substrate, thetemplate having a plurality of openings configured to expose a topsurface of each of the LED dies; depositing a phosphor-containingmaterial on the exposed top surface of each the LED dies; and removingthe template.
 16. The method of claim 15, wherein the template is madeof a material that can be selectively etched from thephosphor-containing material.
 17. The method of claim 15, wherein thetemplate has a non-sticky surface such that the template can be removedfrom the deposited phosphor-containing material.
 18. The method of claim15, wherein the template is a patterned dry photoresist film.
 19. Themethod of claim 15, wherein the plurality of LEDs is formed on asemiconductor substrate.
 20. The method of claim 15, wherein theplurality of LEDs is formed on a silicon wafer.